New Mexico is Taking a Stretch

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Like a waistband after Thanksgiving dinner, New Mexico's borders
are gradually gaining girth, according to the Albuquerque
Journal.

It’s not much, and it’s not happening very fast -- the state is
getting about an inch wider every 40 years -- but the state is
unquestionably expanding, according to University of Colorado
geophysicist Henry Berglund and his colleagues.

Using a collection of 25 extra-precise GPS receivers planted
across New Mexico and Colorado, Berglund determined that the
cities of Albuquerque and Santa Fe are creeping away from each
other. The rate of change seems ever so slow to the untrained
ear, described as approximately 1.2 “nanostrains” per year.

Anne Sheehan, who was Berglund’s faculty adviser and a member of
the research team, told the Journal the phenomenon was actually
surprising and widespread.

The stretching of the surface of the Earth is commonly documented
at the edge of continental plates, where the jigsaw puzzle pieces
that make up the surface of the planet jostle and collide,
forming mountains, or move under or over each other. In places
like California, the effect can be easy to see, the Journal said.

But the effect in continental interiors -- on states not near the
edge of those plates -- was a new one, the scientists said.
Whether an upwelling in the gooey mantle that lies beneath the
crust or a sag in the plates themselves, what exactly drives the
growth remains a mystery.